U.S. patent number 5,906,606 [Application Number 08/607,847] was granted by the patent office on 1999-05-25 for braided body balloon catheter.
This patent grant is currently assigned to Target Therapuetics, Inc.. Invention is credited to Uriel Hiram Chee, Erik T. Engelson, Gene Samson.
United States Patent |
5,906,606 |
Chee , et al. |
May 25, 1999 |
Braided body balloon catheter
Abstract
This is a balloon catheter having braided layer which extends
generally from the proximal end of the catheter to a location
distal of the balloon. In particular, it is desirable that the
shaft of the catheter proximal of the balloon be stiffest at the
proximal section and least stiff just proximal of the balloon.
Although the catheter may be a single lumen catheter using some
type of a core wire to act as a valve for inflation and deflation
of the balloon, it is within the scope of the invention to include
either a separate inflation/deflation lumen or one incorporated
into the various concentric polymeric layers used to make up the
proximal shaft. Particularly preferred is the use of an elastic,
compliant balloon.
Inventors: |
Chee; Uriel Hiram (San Carlos,
CA), Engelson; Erik T. (Menlo Park, CA), Samson; Gene
(Milpitas, CA) |
Assignee: |
Target Therapuetics, Inc.
(Fremont, CA)
|
Family
ID: |
27074283 |
Appl.
No.: |
08/607,847 |
Filed: |
February 27, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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566802 |
Dec 4, 1995 |
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Current U.S.
Class: |
604/527; 604/246;
606/192; 606/194; 604/96.01 |
Current CPC
Class: |
A61M
25/10 (20130101); A61M 25/1027 (20130101); A61M
25/005 (20130101); A61M 25/0054 (20130101); A61M
2025/0079 (20130101); A61M 25/0053 (20130101); A61M
2025/09183 (20130101) |
Current International
Class: |
A61M
25/10 (20060101); A61M 25/00 (20060101); A61M
025/00 () |
Field of
Search: |
;604/280-282,264,96,97,99,246 ;128/656,658 ;606/192,194 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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0 205 851 |
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Dec 1986 |
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EP |
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0 358 117 |
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Mar 1990 |
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EP |
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2 172 205 |
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Sep 1986 |
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GB |
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2233562 |
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Jan 1991 |
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GB |
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WO 93/20881 |
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Oct 1993 |
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WO |
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WO 94/27668 |
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Dec 1994 |
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WO |
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WO 95/23626 |
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Sep 1995 |
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WO |
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Primary Examiner: McDermott; Corrine
Assistant Examiner: Rodriguez; Cris L.
Attorney, Agent or Firm: Morrison & Foerster L.L.P
Parent Case Text
RELATED APPLICATIONS
This a continuation-in-part of U.S. patent application Ser. No.
08/566,802, filed Dec. 4, 1995, now abandoned, entitled "Braided
Body Balloon Catheter", the entirety of which is incorporated by
reference.
Claims
We claim as our invention:
1. A single lumen balloon catheter assembly comprising:
a) an elongate tubular member having a distally located balloon
portion having an inflatable balloon and a proximally located shaft
portion having a proximal end and a distal end,
b) a distally open ended central lumen extending through said
balloon portion and said shaft portion and wherein said central
lumen is in fluid communication with said inflatable balloon,
and
c) a braided member extending from the shaft portion proximal end
to a point located distally of the balloon portion, whereby said
inflatable balloon may be inflated from said central lumen.
2. The balloon catheter assembly of claim 1 wherein the shaft
portion further comprises an outer covering member exterior to the
braided member.
3. The braided catheter assembly of claim 2 wherein the outer
covering member has a distal end proximally abutting the inflatable
balloon.
4. The balloon catheter assembly of claim 1 wherein the inflatable
balloon comprises an elastic material.
5. The balloon catheter assembly of claim 1 wherein the inflatable
balloon comprises a fixed diameter inflatable balloon.
6. The balloon catheter assembly of claim 1 wherein the shaft
portion further comprises a lubricious inner liner member which is
interior to the braided member and forms the central lumen.
7. The balloon catheter assembly of claim 1 wherein the proximal
end of the shaft portion is stiffer than the distal end of the
shaft portion.
8. The balloon catheter assembly of claim 7 wherein the shaft
portion has at least three sections, the most proximal of said
sections being the stiffest, the most distal of said sections being
the least stiff, and at least one of said sections between said
most proximal section and said most distal section having a
flexibility intermediate that of the most proximal section and the
most distal section.
9. The balloon catheter assembly of claim 1 wherein the braid is a
woven braid.
10. The balloon catheter assembly of claim 1, further comprising a
valve seat situated in said balloon catheter assembly central lumen
distally of the balloon portion.
11. The balloon catheter assembly of claim 10, further comprising a
lubricious inner liner member interior to the braided member and
forming at least a portion of the central lumen.
12. The balloon catheter assembly of claim 10, further comprising a
valve wire extendible through the central lumen and having thereon
a cooperating valve plug adapted to engage the valve seat either
distally or proximally.
13. The balloon catheter assembly of claim 1, further comprising a
radio-opaque marker distally of the inflatable balloon.
14. The balloon catheter assembly of claim 1 wherein the braided
member comprises super-elastic alloy ribbons.
15. The balloon catheter assembly of claim 1 wherein said braided
member comprises a braided shaft section extending from the shaft
portion proximal end to a point proximal to the inflatable balloon
and a braided balloon section extending through said balloon
portion, said braided shaft section having an outer covering member
exterior to the braided member and said braided balloon section
having no cover member associated therewith.
16. The balloon catheter assembly of claim 15 wherein said braided
balloon section further comprises a plurality of openings, said
openings providing a fluid passageway between said central lumen
and said inflatable balloon.
17. The balloon catheter assembly of claim 16 wherein said braided
member comprises metallic wires or ribbons.
18. A single lumen balloon catheter assembly comprising an elongate
tubular member having
a) a distally located balloon portion having an inflatable
balloon,
b) a proximally located shaft portion having at least three
sections, the most proximal of said sections being the stiffest,
the most distal of said sections being the least stiff, and at
least one of said sections between the most proximal section and
the most distal section having a flexibility intermediate that of
the most proximal section and the most distal section, and
c) a braided member extending from said proximal section to a point
located distally of said inflatable balloon,
and wherein said elongate tubular member has a distally open ended
central lumen in fluid communication with said inflatable balloon
extending through both said balloon portion and said shaft portion
and whereby said inflatable balloon may be inflated using said
central lumen.
19. The balloon catheter assembly of claim 18 wherein the shaft
portion further comprises an outer covering member exterior to the
braided member.
20. The braided catheter assembly of claim 19 wherein the outer
covering member has a distal end proximally abutting the balloon
portion.
21. The balloon catheter assembly of claim 18 wherein the
inflatable balloon comprises an elastic material.
22. The balloon catheter assembly of claim 18 wherein the
inflatable balloon is a fixed diameter inflatable balloon.
23. The balloon catheter assembly of claim 18 wherein the shaft
portion further comprises a lubricious inner liner member which is
interior to the braided member and forms the central lumen.
24. The balloon catheter assembly of claim 23 wherein the
lubricious inner liner extends distally of the balloon portion and
has an inner lumen forming the central lumen and has an outer
surface defining one or more inflation passageways in fluid
communication with the inflatable balloon.
25. The balloon catheter assembly of claim 18, further comprising a
valve seat situated in said central lumen distally of the balloon
portion.
26. The balloon catheter assembly of claim 25, further comprising a
lubricious inner liner member interior to the braided member and
forming at least a portion of the central lumen.
27. The balloon catheter assembly of claim 25, further comprising a
valve wire extendible through the balloon catheter assembly central
lumen and having thereon a cooperating valve plug adapted to engage
the valve seat either distally or proximally.
28. The balloon catheter assembly of claim 18, further comprising a
radio-opaque marker distally of the inflatable balloon.
29. The balloon catheter assembly of claim 18 wherein the braided
member comprises super-elastic alloy ribbons.
30. A single lumen balloon catheter assembly comprising an elongate
tubular member comprising:
a.) a distally located balloon portion having an inflatable
balloon,
b.) a proximally located shaft portion having a proximal end and a
distal end, and
c.) a braided member extending from the shaft portion to a point
located distally of the balloon portion, and wherein a distally
open ended central lumen extends at least from said shaft portion
distally through said balloon portion.
31. The balloon catheter assembly of claim 30 wherein said braided
member extends from said shaft portion proximal end.
32. The balloon catheter assembly of claim 31 wherein the shaft
portion further comprises a lubricious inner liner member interior
to the braided member, said inner liner forming the central
lumen.
33. The balloon catheter assembly of claim 30 wherein the shaft
portion further comprises a polymeric outer covering member
exterior to the braided member.
34. The braided catheter assembly of claim 33 wherein the outer
covering member has a distal end ending proximal of said balloon
portion.
35. The balloon catheter assembly of claim 33 wherein the shaft
portion further comprises a lubricious inner liner member interior
to the braided member and forms the central lumen.
36. The balloon catheter assembly of claim 35 wherein the polymeric
outer covering member comprises a member selected from
polyethylene, polyvinyl chloride, ethylvinyl acetate, polyethylene
terephthalate, and polyurethane, and their mixtures and block or
random copolymers.
37. The balloon catheter assembly of claim 36 wherein the
lubricious inner liner member comprises a polyfluorocarbon.
38. The balloon catheter assembly of claim 36 wherein the
lubricious inner liner member adheres to the polymeric outer
covering member.
39. The balloon catheter assembly of claim 35 wherein the
lubricious inner liner member comprises a polyfluorocarbon.
40. The balloon catheter assembly of claim 30 wherein the
inflatable balloon comprises an elastic material.
41. The balloon catheter assembly of claim 30 wherein the
inflatable balloon comprises a fixed diameter inflatable
balloon.
42. The balloon catheter assembly of claim 30 wherein the shaft
portion further comprises a lubricious polymeric inner liner member
which is interior to the braided member and forms the central
lumen.
43. The balloon catheter assembly of claim 42 wherein the inner
lumen forming the central lumen has one or more inflation
passageways therein between said central lumen and the inflatable
balloon.
44. The balloon catheter assembly of claim 43, further comprising a
valve seat situated in said balloon catheter assembly central lumen
distally of the balloon portion and adapted to cooperate with a
guidewire having a valve member located distally to close said
central lumen.
45. The balloon catheter assembly of claim 44, further comprising
in combination a guidewire at least partially located within said
central lumen and having a valve member located distally of said
valve seat.
46. The balloon catheter assembly of claim 44, wherein the balloon
portion comprises an inflatable balloon having an outer wall with
orifices therein.
47. The balloon catheter assembly of claim 42 wherein the
lubricious inner liner extends distally of the balloon portion and
has an inner lumen forming the central lumen and has an outer
surface defining one or more inflation passageways in fluid
communication with the inflatable balloon.
48. The balloon catheter assembly of claim 30 wherein the proximal
end of the shaft portion is stiffer than the distal end of the
shaft portion.
49. The balloon catheter assembly of claim 30 wherein the shaft
portion has at least three sections, the most proximal of said
sections being the stiffest, the most distal of said sections being
the least stiff, and at least one of said sections between the most
proximal section and the most distal section having a flexibility
intermediate that of the most proximal section and the most distal
section.
50. The balloon catheter assembly of claim 30, further comprising a
radio-opaque marker distal in the inflatable balloon.
51. The balloon catheter assembly of claim 50, further comprising a
radio-opaque marker proximal of the inflatable balloon.
Description
FIELD OF THE INVENTION
This invention is a surgical device. In particular it is a balloon
catheter having a braided layer which extends generally from the
proximal end of the catheter to a location distal of the balloon.
In particular, it is desirable that the shaft of the catheter
proximal of the balloon be stiffest at the proximal section and
least stiff just proximal of the balloon. Although the catheter may
be a single lumen catheter using a core wire acting as a valve for
inflation and deflation of the balloon using that single lumen, it
is within the scope of the invention to include either a separate
inflation/deflation lumen or one isolated from the central lumen
and incorporated into the various coaxial layers used to make up
the catheter. Particularly preferred is the use of an elastic,
compliant balloon which may be inflated and deflated through the
lumen provided for that purpose. Catheters having "leaky" balloons
are also suitable in this invention.
BACKGROUND OF THE INVENTION
This invention relates generally to a highly flexible catheter
having a balloon at its distal tip. The form of the catheter is
such that it may be used in various percutaneous transluminal
angioplasty (PTA) procedures but is sufficiently flexible in its
construction that it may be used for other diagnostic and treatment
indications in regions of the body having significantly more
tortuous vasculature.
For instance, in PTCA procedures, a guiding catheter typically
having a preshaped distal tip is introduced into the vasculature of
a patient. The catheter is advanced from the entry point, up into
the aorta and, once at that site, is twisted or torqued from the
proximal end of the catheter so to turn the preshaped distal tip of
the guiding catheter in to the ostium of a desired coronary artery.
A balloon-bearing or "dilatation" catheter is then advanced through
the lumen of a guiding catheter and is progressed out the guiding
catheter's distal tip until the balloon on the distal extremity of
the dilatation catheter extends cross the region to be dilated. The
balloon is then expanded, typically to a predetermined size
dictated by the design of the balloon, via the use of radio-opaque
liquid at relatively high pressures. Upon completion of the
procedure, the balloon is then deflated so that the dilatation
catheter can be removed and blood flow resumed through the
thus-treated artery.
In other procedures, a balloon-bearing catheter typically of a
somewhat smaller diameter than a catheter used in PTA or PCTA might
be used. In a universal sense, the procedure might be considered to
be similar in that a larger or guiding catheter is initially placed
so that its distal end is near the body site to be treated or
diagnosed. The balloon-catheter, perhaps with the guidewire through
an existing central lumen, would then be extended from the distal
end of the guiding catheter to the site. The balloon is expanded
and once the procedure is complete, the balloon is deflated and
removed from the body. In some instances, the balloon might be of a
compliant nature rather than the fixed diameter configuration found
in a typical PTA balloon.
The advent of interventional radiology as a viable alternative in
neurological regions of the body have produced demands on
catheterization equipment not faced by demands placed on PTCA
devices. The need for significantly smaller diameter devices,
devices having a variable flexibility, ability to resist kinking
(particularly in those regions where the differences in flexibility
may be acute) is notable.
One way to produce strong catheter shafts for a balloon catheter is
via the use of braids in those shafts. For instance, U.S. Pat. No.
5,338,295, to Cornelius et al. describes a dilatation balloon
catheter having a shaft formed of a tubular stainless steel braid.
The proximal outer tube section is encased in a polyimide material.
The distal outer tube section which forms the balloon is made of a
polymeric material such as polyethylene. The braid in this instance
extends only partially down the proximal portion of the catheter.
It does not extend as far as the balloon nor does it extend through
the balloon.
Another similar device is shown in U.S. Pat. No. 5,451,209, to
Ainsworth et al. Ainsworth et al. describes a composite tubular
element useful in intravascular catheters. In particular it is
shown as an element, variously of a fixed wire dilatation catheter
and in a guiding or angiographic catheter. The structure of the
device is made by braiding strands from a mixture of a polymeric
matrix materials (such as fibers or powders) having a relatively
low melting point and a high strength reinforcing fiber having a
relatively high melting point. The fibers are woven into a tubular
element; the resulting braided tubular element is heated to melt
the low melting point matrix material so as to flow around the
reinforcing fibers to form a matrix. Thermoplastic jackets or
coatings are then extruded or otherwise applied to the exterior of
the thus-produced braided tubular element. There is no suggestion
in the patent to either produce a shaft which has variable
stiffness proximally nor to use only a metallic braid from the
proximal end of a over the wire catheter to a position distal of
the balloon.
U.S. Pat. No. 5,429,597 to DeMello, teaches a balloon catheter
which is said to be kink resistant. In general, it appears to be
made up of an outer polymeric covering over a "cross-wound
multifilar (CWMF)" coil and a non-fixed, removable core wire. The
CWMF coil is a pair of helical coils which are wound in opposite
directions to provide for torque transmission during use. There
appears to be no suggestion of weaving the CWMF into a braid. There
is no suggestion of extending the CWMF through the length of the
balloon interior.
The PCT application to Pray et al. (WO 93/20881) assigned to Scimed
Medical Systems suggests a dilatation catheter having a shaft with
a proximal section which is a composite of polymeric material and a
stainless steel braid tube. The distal section of the catheter is
formed of a flexible polymeric tube. In one embodiment of the
described device, the braid weave of the proximal section of the
shaft has a varying pick count, increasing in the distal direction,
thereby providing for increased flexibility in the distal
direction. However, this document does not suggest the use of a
braided tube extending distally of the balloon. Furthermore, there
is no suggestion of the use of an elastomeric or rubbery balloon on
the device.
Published UK Patent Application G.B. 2,233,562A, by Hannam et al.,
shows a balloon catheter having a flexible, hollow inner shaft and
an outer braided shaft with a balloon inflated by fluid introduced
between the inner and outer shafts. The inner shaft is fixed
relative to the outer shaft at both ends. When the balloon is
inflated, the outer shaft shortens. The excess length of the inner
shaft is accommodated via the inner shaft bending into a coil-like
form. The braid is said typically to be of a fabric of a polyester
floss. It is said to extend the entire length of the outer shaft
but with a varying pick rate apparently in the neighborhood of the
balloon. The balloon is made of the material of the loose braided
layer and a flexible, elastic polyurethane. There is no suggestion
of using the braided material as an overall stiffener in the
balloon catheter device. There is no suggestion of placing the
braid on the interior of the balloon.
None of the published documents teaches the inventive balloon
catheter.
SUMMARY OF THE INVENTION
This invention is a catheter used for insertion into some lumen of
the human body. In general, it may be used in a vascular lumen but
is suitable for treatment of other body lumen as may be found in
the genito-urinary systems, the biliary system, or wherever else a
remotely controllable balloon is desired.
The physical structure of the inventive balloon catheter includes a
braid of either ribbon or wire, which extends generally from the
proximal end of the catheter to a region on the distal end of the
catheter assembly, preferably distal of the balloon. Typically, the
braid has a polymeric tubing member externally and internally, both
adjacent the braid member. The polymers of those adjacent tubing
members may fill the interstices of the braid member or an adhesive
may be used if so desired. In a preferred variation, the openings
in the braided tubular member may function as a fluid passageway
between the inner lumen of the catheter into the balloon itself.
Further, in a most desirable aspect of this invention, the braid
acts as a stiffener both at the region just proximal of the balloon
and for the balloon itself. This is especially useful when the
catheter is of the type having decreasing stiffness between the
proximal end of the catheter and a point just proximal of the
balloon.
The catheter most desirably has an inner layer of lubricious
polymeric tubing. The inner lubricious layer may extend all the way
to the distal tip or may extend into the region just proximal and
distal of the proximal end of the balloon. This helps somewhat with
stiffness and kinking control at the critical proximal end of the
balloon. The catheter, when it is a single lumen catheter having an
open distal end, may include passageways from the inner lumen
through the inner lubricious layer and braid into the balloon. As
noted above, if the inner lubricious layer does not extend
completely through the interior of the balloon, the inflation fluid
may pass radially through the braid wall.
When the balloon catheter is a single lumen catheter, it is quite
desirable that the portion just distal of the balloon be fitted
with a valve seat in its lumen so to cooperate with a valve seat
found on a core wire or guide wire. In this way, the user of the
balloon catheter may introduce the inflation fluid through the
single lumen into the balloon and inflate that balloon merely by
seating the core wire's valve member onto the valve seat provided
in the catheter lumen.
Another variation of this invention includes the provision of cast
or extruded passageways in the outer surface of inner lubricious
tubing so that the passageways are in communication with the
balloon. In this way, the balloon may be inflated and deflated
using these ancillary openings and yet the inner central passageway
may be used for a number of other purposes.
Finally, the balloon member used in this inventive catheter
assembly may be either elastomeric and radially compliant to
provide for a variety of functions not typically attempted by use
of a polyethylene balloon.
The concept of this inventive balloon catheter is the provision of
a highly flexible, highly compliant balloon catheter which is
amenable to use in very distal vasculature. It is designed in such
a way that in spite of the fact that it has very high flexibility,
it is also quite resistant to kinking, particularly in the region
just proximal of the balloon.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a plan view of one highly desirable variation of an
overall assembly of the invention.
FIG. 2A shows a partial cutaway of the shaft portion of the
inventive catheter showing a wire type braid. FIG. 2B shows a full
cutaway of the FIG. 2A depiction.
FIG. 3A shows a partial cutaway, side view of a catheter shaft made
according to the invention using a ribbon type braid. FIG. 3B shows
a full cutaway of the FIG. 3A depiction.
FIGS. 4 and 5 show cutaway, side views of two variations of the
inventive balloon catheter.
FIG. 6A shows a cutaway, side view variation of the distal end of
the inventive catheter. FIG. 6B shows a cross section of the shaft
of the FIG. 6A variation showing the inflation lumens placed at the
outer surface of the inner lubricious layer.
FIG. 7 shows a cutaway, side-view of a "leaker" balloon suitable
for use in this inventive catheter.
DESCRIPTION OF THE INVENTION
FIG. 1 shows a side view of a catheter assembly, generally
designated (100), made according to the invention. The catheter
assembly (100) comprises an elongate tubular member with a balloon
section (102) at the distal end of the catheter, body section (104)
proximal of balloon section (102), and a proximal section (106).
The catheter assembly (100) is designed generally for operation in
combination with a flexible guide-wire (107) preferably with a
bendable guiding tip (112) which is often a coil. The guide-wire is
used to guide the catheter assembly (100) along complicated and
tortuous pathways typically in the human vasculature to a target
site within the body. The design of guidewire (107) may be of any
convenient design which allows manipulation of the combined
catheter (100) and the guidewire (107) to the desired site. The
overall length of the catheter assembly is typically between 30 cm
and 175 cm, depending on the portion of the body to be reached by
the catheter (100) through the chosen body access site. For
instance, if the chosen site is within the brain and the femoral
artery in the groin is the access site, the length of the catheter
(100) would be in the higher regions of noted range. If the access
is through the neck, as would be the case with significantly obese
patients, the overall length of the catheter can be much
shorter.
At the proximal end of the catheter device (100) is shown an end
fitting (110) through which the guidewire may be received and
through which fluid material may be introduced into the catheter
lumen. One suitable fitting has an axially extending port through
which the guidewire is rotated and advanced or retracted axially
within the catheter, during a catheter placement operation. A side
port may be used to deliver other fluid materials through the
catheter to the target site potentially after removal of the
guidewire.
One concept central to this particular invention is to be noted in
that the portion of the catheter assembly (100) which is proximal
of balloon (114) typically is of stepped or staged flexibility.
That is to say that proximal section (106) is stiffer than
mid-section (104), which in turn is stiffer than the portion of
balloon section (102) which is found proximal of balloon (108). In
a very general sense, this sequence of flexibilities allows a
catheter such as shown here to follow the increasingly more narrow
vasculature as the catheter is progressed within the body from the
entrance point to the target site within the body. Although three
sections of different flexibility are shown here, it is not
necessary that the number of sections be only three. It may be four
or six or ten, depending upon the needs of the designer providing
for the detailed variation of this catheter and the needs of the
attending physician in introducing it to the human body. Indeed, it
may be that one or more of the sections may be continuously
variable in flexibility as a function of the axial length. For
instance, it might be highly desirable to have a proximal section
(106) which is of a single flexibility so to allow ease of
pushability and access through a guiding catheter and yet have
mid-section (104) and balloon section (102) be continuously
variable in stiffness. That the proximal section is significantly
stiffer than the portion of the balloon section (102) proximal of
the balloon is significant to this invention.
The balloon (114), as was noted above, is shown in balloon section
(102). The presence of the balloon is obviously central to this
invention.
Also central to this invention is the use of a braided layer
positioned within the wall of the catheter assembly (100). FIG. 2A
shows a partial cutaway side view of a section of the inventive
catheter (100) which is proximal of the balloon (114) (see FIG. 1).
In this cutaway may be seen an outer covering (200), an inner liner
(202) and the braid (204) positioned between the two layers. FIG.
2B shows the structure in greater detail because of its full
cutaway depiction. The outer covering (200) is again shown in
cross-section. The inner liner (202) and the wires making up braid
(204) are shown in cross-section. As shown in FIG. 2, both outer
covering member (200) and inner member (202) are polymeric. They
are desirably selected of materials which tack to each other upon
heating. They may also be melt-miscible. In some instances, they
may contain components which act in the manner of adhesives, but
such is not necessary. Typically, for the simple variation shown in
FIGS. 2A and 2B, the outer covering member (200) is of a material
which may be heat-shrinkable onto the inner member (202) and the
braid member (204). Preferred polymeric materials for the outer
layer (200) include such materials as polyethylene, polyvinyl
chloride (PVC), ethylvinyl acetate (EVA), polyethylene
terephthalate (PET), and polyurethane, and their mixtures and block
or random copolymers. Clearly, such materials as PVC and
polyurethane are not of the type which are heat-shrinkable onto the
outer layer of the catheter section. Other methods may be chosen to
place these materials on the outer section of the catheter. One
such procedure involves slipping the inner section (202) and braid
(204) onto a mandrel of appropriate size to support the diameter of
the inner section. A length of tubing of a material suitable for
the outer covering member (200) and a heat-shrinkable tubing
exterior is then slipped over the combination of the inner section
(202), braid (204), mandrel. Upon selection of the proper
temperature-dependent physical parameters of the respective
polymers, the heat-shrink tubing may be used to squeeze a polymeric
material--e.g., polyurethane--onto the braid (204) when the
heat-shrink temperature is above the glass transition temperature
of the outer layer (200). The heat-shrinkable tubing may then be
stripped off before further assembly of the catheter or, obviously,
before use.
Another useful class of polymers are thermoplastic elastomers,
including those containing polyesters as components. Typical of
this class is materials sold as Hytrel. Additionally, an adhesive
may be coated onto the inner liner tubing. Polyesters and
polyimides, in particular, care useful as adhesives on its
surface.
Inner liner (202) is a thin (preferably less than about 0.0015
inches) tubing of a lubricious polymer such as a polyfluorocarbon.
Although a wide variety of materials are generically suitable in
the service, thin layers may be made of polytetrafluoroethylene
(PTFE) or fluoroethylene polymers (FEP). This inner liner (202)
runs generally from the proximal portion of the catheter assembly
(100 in FIG. 1) to some point at least just proximal of the balloon
(114 in FIG. 1). The fluoropolymers may be etched to provide a
surface to which other polymers may adhere. The outer covering
member (200) may be treated or heated so to allow penetration of
the polymer in the outer covering member (200) through the openings
in the braid and allow such adherence.
It should be noted that each of the polymers described herein may
be doped or filled with radio-opaque materials such as barium
sulfate, bismuth trioxide, bismuth carbonate, powdered tungsten,
powdered tantalum or the like so that the location of various
portions of the catheter sections may be radiographically
visualized as present in the human body.
FIG. 3A shows another catheter section (206) having an outer
covering (200), an inner liner (202), and a braid (208). In this
case, the braid is constructed of a flat ribbon of a metal or alloy
rather than the wire-shaped braid members shown in FIGS. 2A and 2B.
Similarly, FIG. 3A shows a full cross-section of the catheter
section (206) with an outer covering (200), an inner lubricious
tubular member (202) and the braided member (208) in a
cross-section.
As should be apparent from this description, it is within the scope
of this invention to have multiple polymeric layers exterior of the
braid (204 or 208), as well as of multiple polymeric liner members
interior to braid (204 or 208). Furthermore, it is within the scope
of the invention to include multiple braids and/or flat ribbon
coils between or amongst the various polymeric layers.
It is also within the scope of this invention to coat at least one
of the exterior surfaces of outer member (200) with a lubricious
coating, whether such coating is chemically bonded to the layer or
is merely physically coated onto the relevant surface. A
description of suitable procedures for producing such lubricious
coatings is found in U.S. patent application Ser. Nos. 08/060,401
("LUBRICIOUS CATHETERS"), filed May 12, 1993; 08/235,840 ("METHOD
FOR PRODUCING LUBRICIOUS CATHETERS"), filed Apr. 29, 1995; and
08/272,209 ("LUBRICIOUS FLOW-DIRECTED CATHETER"), filed Jul. 8,
1994, the entirety of which are incorporated by reference.
The metallic braid shown in FIGS. 2A, 2B, 3A, and 3B is preferably
made up of a number of metallic ribbons, as shown in FIGS. 3A and
3B, although wire-based braids, as shown in FIGS. 2A and 2B are
also acceptable if a site diameter penalty is acceptable.
Preferably a majority of the metallic ribbons are wires in braids
(204) or (208) are members of a class of alloys known as
super-elastic alloys.
Preferred super-elastic alloys include titanium/nickel alloys,
particularly materials known as nitinol--alloys which were
discovered by the U.S. Naval Ordnance Laboratory. These materials
are discussed at length in U.S. Pat. Nos. 3,174,851 to Buehler et
al., 3,351,463 to Rozner et al. and 3,753,700 to Harrison et al.
Commercial alloys containing some amount, commonly up to about 5%,
of one or more other members of the iron group, e.g., Fe, Cr, Co,
etc., are considered to be encompassed within the class of
super-elastic Ni/Ti alloys suitable for this service. When using a
braid containing some amount of a super-elastic alloy, an
additional step may be desirable to preserve the shape of the
stiffening braid. For instance, with a Cr-containing Ni/Ti
superelastic alloy which has been rolled into 1.times.4 mil ribbons
and formed into a 16-member braid, some heat treatment is
desirable. The braid may be placed onto a, e.g., metallic, mandrel
of an appropriate size and then heated to a temperature of 600
degrees Fahrenheit to 750 degrees Fahrenheit for a few minutes, to
set the appropriate shape. After the heat treatment step is
completed, the braid retains its shape and the alloy retains its
super-elastic properties.
Other materials which are suitable for the braid include stainless
steels (AISI 303, 308, 310 and 311).
Metallic ribbons (208) that are suitable for use in this invention
desirably are between 0.25 mil and 3.5 mil in thickness and 2.5 mil
and 12.0 mil in width. By the term "ribbon", we intend to include
elongated cross-sections such as a rectangle, oval, or semi-oval.
When used as ribbons, these cross-sections should have an aspect
ratio of thickness-width of at least 0.5.
It is within the scope of this invention that the ribbons or wires
making up the braid also be of materials other than super-elastic
alloys. A minor amount of fibrous materials, both synthetic and
natural, may also be used. In certain applications, particularly in
smaller diameter catheter sections, more malleable metals and
alloys, e.g., bold, platinum, palladium, rhodium, etc., may be
used. A platinum alloy with a few percent of tungsten is sometimes
preferred partially because of its radio-opacity.
Suitable nonmetallic ribbons or wires include materials such as
those made of polyaramides (Kevlar), polyethylene terephthalate
(Dacron), or carbon fibers. The braids used in this invention may
be made using commercial tubular braiders. The term "braid" is
meant to include tubular constructions in which the ribbons making
up the construction are woven in an in-and-out fashion as they
cross, so as to form a tubular member defining a single lumen. The
braid members may be woven in such a fashion that 2-4 braid members
are woven together in a single weaving path. Typically, this is not
the case. It is much more likely that a single-strand weaving path,
as is shown in FIGS. 2A and 3A is used.
The braid shown in FIGS. 2A and 3A has a nominal pitch angle of 45
degrees. Clearly the invention is not so limited. Other braid
angles from 20 degrees to 60 degrees are also suitable. One
important variation of this invention is the ability to vary the
pitch angle of the braid either as the braid is woven or at the
time the braid is included in catheter section or sections. In this
way, the braid itself may be used to vary the flexibility of
various sections of the catheter.
FIG. 4 shows the distal tip of catheter such as shown in FIG. 1 in
cross-section. In this variation, the outer covering element (200)
is shown abutting balloon (114). As was noted above, the end of the
inner liner (202) extends distally of the most proximal portion of
the catheter and terminates just at the edge of balloon (114). The
braid member (in this case ribbon braid (208)) also extends from
some site approximately of the balloon to terminate near the distal
end of balloon (114). The braid has a number of functions in this
and the following variations. In particular, it stiffens the
balloon (114) itself and at least in this instance serves as the
passageway for fluid flow between the lumen of braid (208) and the
balloon (114). This openings between the ribbons of the ribbon
braid (208) also allow for deflation of the balloon. Control of the
inflation fluid is achieved by the use of valve seat (210). The
inner radius of valve seat (210) is a size to engage cooperatively
a ball or other appropriate shape placed on a guide wire or core
wire in a manner known in the prior art. As the valving is engaged
either distally or proximally on valve seat (210) (depending on
whether the control wire is inserted from the distal end or the
proximal end of the catheter) the single opening for releasing the
fluid from the catheter is closed and any additional fluid
introduced into the lumen of the catheter itself will inflate the
balloon (114). The balloon may be deflated using reverse of that
procedure. Also shown in FIG. 4 is a distal radio-opaque marker
(212) and a proximal radio-opaque marker (214). These two markers
(212 and 214) are shown to be coils for ease of display. They may
also be bands or other markers known in the art. Markers of this
type are typically made of materials such as those listed above,
e.g., platinum, gold, and various related alloys. These markers are
individually optional in this invention. Other means are known for
locating the position the balloon at the distal end of the
catheter.
As noted above, one of the major reasons for carrying the braid
member (208) from the proximal end of the balloon down through the
distal end of the balloon (114) is to assure that the joint between
the portion of section (102) just proximal of the balloon and the
balloon itself is strengthened. Kinking often occurs proximally of
the balloon because of the difference in stiffness between the
balloon (114) and its proximal neighbor section.
The balloon (114) itself is desirably produced from elastomeric
material. Many balloons used on balloon catheters are produced of
material such as polyethylene. Polyethylene balloons are not
elastomeric. Such balloons are merely folded axially to accommodate
passage of the distal tip of the catheter assembly through a
guiding catheter and then through narrow curvatures in the
vasculature. It is difficult to bend such a folded balloon and
consequently it is not always as maneuverable as it desirably could
be. An elastomeric balloon, on the other hand, is simply
inflatable. It need not be folded. The catheter design described
here is suitable for any size of catheter, but for use in very
narrow portions of the vascular, the axial length of the balloon
should be between 2 mm and 10 mm. The non-expanded diameter may be
between 0.035 inches and 0.064 inches for neurosurgical devices.
For other uses, the distal end of the catheter (100) may be 0.120
inches or larger. The elastomeric balloon (114) is preferably of a
material such as natural or synthetic rubbers, silicones,
polyurethanes, and their block or random copolymers. One especially
useful class of materials are elastomeric urethane copolymers,
e.g., polyurethane/polycarbonate thermoplastics such as Carbothane
sold by Thermedics. Adhesives may be used to seal the balloon (114)
against the outer tubing covering (200). A polymeric hydrophilic
coating over the balloon (114) and the inner surfaces of inner
tubing (202) may be desirable.
The balloon section (102) is perhaps the most flexible portion of
the catheter assembly and typically comprises about five to 35% of
the overall length of the catheter assembly (100).
FIG. 5 shows another variation of distal tip of the inventive
catheter in which the braid (204) is based on wire rather than
ribbon and the inner lubricious liner (202) extends to some
position interior of the balloon (114). This provides some
additional stiffening to the overall design in the more distal
portion of the inventive device. The radio-opaque marker (212) is
displayed distally to the balloon (114) and is shown as a single
presence. No matching or complimenting radio-opaque marker is found
proximally of balloon (114). The variation shown in FIG. 5 are
merely for the purpose of depicting differences and not for
limiting the noted structure in any way. A braid based on a ribbon
may just as well be used in this variation. Additional radio-opaque
markers may also be used. Also shown in this variation is the
presence of several holes in the wall of the inner liner (202).
These holes (216) permits additional passage of fluid from the
interior of the inner lubricious tubing (202) into the balloon
(114).
FIGS. 6A and 6B show a significantly different variation of the
inventive catheter assembly. In this variation, the distal-most
portion of the catheter is without a valve seat of the type shown
in FIGS. 4 and 5. In this variation, the inner lumen (220) of the
catheter is not in fluid communication with the balloon (114). The
inner lubricious tubing section (222) is sealed at the distal tip
of the catheter. This variation is shown with a wire type braid
(204) but as above, a ribbon braid may be used in its stead. The
balloon is inflated using one or more inflation passageways (224)
found in liner (222). Fluid passes through the inflation
passageways (224) from the proximal end of the catheter assembly
through the interstices between the turns and weaves of the braid
into the balloon (114). Deflation is carried out by use of the same
fluid passageway or passageways. This design provides for
unfettered use of the central lumen (220) without interference with
a guide wire. High fluid flow catheters would desirably be of this
design.
FIG. 7 shows another variation of the inventive catheter. In this
instance, the balloon (240) has one or more orifices (242) which
serve as "leakers" to allow the fluid filling the balloon (240) to
leak slowly from the interior. This variation of the catheter
assembly is designed primarily to hasten access of the catheter tip
to a selected treatment site. The central lumen (244) is designed
to accommodate a guidewire (246) having a valve member (248)
situated external to the distal tip of the catheter assembly. As
the guidewire (246) is withdrawn proximally, the valve member (248)
fits against the tip (250) of the catheter and seals against the
catheter. Fluid injected into the lumen (244) of the catheter
passes through the passageways (252) provided and into the balloon
(240). The balloon (240) inflates. Once inflated, the holes (242)
allow the fluid to pass slowly into the body lumen. This
combination of catheter is especially effective in accessing remote
sites because the balloon acts as a sail, the size of which may be
modulated by coordination of the fluid introduction and leak rate.
The speed of the combination is caused thus: the balloon is used
when a high flow region in the vasculature is encountered; the
balloon is deflated and the guidewire is used to select one branch
of a bifurcated pathway when the selected pathway does not evidence
the higher flow. The braided shaft located in the proximal section
allows the physician to push with the confidence that the catheter
will follow the chosen path without kinking at any point.
Many alterations and modifications may be made by those of ordinary
skills in the art without departing from the spirit and scope of
this invention. The illustrated embodiments have shown only for
purposes of clarify. The examples should not be taken as limiting
this invention as defined by the following claims which claims
includes all equivalents, whether those equivalents are now or
later devised.
* * * * *